SEALING RING MADE OF A HIGH-PERFORMANCE THERMOPLASTIC MATERIAL AND LIQUID SILICONE

Abstract

A sealing ring for a header of an implantable device has an outer ring and an inner ring. The outer ring is formed with, or of, a high-performance thermoplastic material. The inner ring is formed with, or of, liquid silicone or polyurethane. The inner and outer rings are arranged with a form-fit relative to each other. There is also described a method for manufacturing such a sealing ring and also a contact socket and an implantable device with such a sealing ring.

Claims

1. A sealing ring for a header of an implantable device, the sealing ring comprising: an outer ring formed with, or consisting essentially of, a high-performance thermoplastic material being a polyaryl or a liquid-crystal polymer, with the polyaryl being selected from the group consisting of a poly(aryl ether sulfone), a polyaryletherketone, and a polyphenylene sulfide; and an inner ring formed with, or consisting essentially of, a liquid silicone or a polyurethane; wherein said inner ring and said outer ring are arranged with a form fit relative to one another.

2. The sealing ring according to claim 1, wherein said inner ring is formed with at least one groove having a base and two opposite sides that extend from said base, and said outer ring engages in said groove with a form-fit engagement.

3. The sealing ring according to claim 2, wherein said outer ring is formed with at least one aperture and said inner ring has at least one bar, which extends from one side of said groove to the other side of the groove, and said at least one bar passes through said at least one aperture.

4. The sealing ring according to claim 3, wherein said at least one aperture formed in said outer ring is a slot.

5. The sealing ring according to claim 1, wherein said liquid silicone is selected from a two-component mixture of any Shore hardness which is biocompatible.

6. The sealing ring according to claim 1, wherein said outer ring is an injection-molded element.

7. The sealing ring according to claim 1, wherein said inner ring is injection-molded around said outer ring.

8. A contact socket for an implantable medical device, the contact socket comprising at least one sealing ring according to claim 1.

9. An implantable device, comprising a sealing ring according to claim 1 or a contact socket according to claim 8, and being an implantable cardioverter-defibrillator or an implantable spinal cord stimulator.

10. A method for producing a sealing ring, the method comprising the following steps: providing an outer ring formed with, or consisting essentially of, a high-performance thermoplastic material selected from the group consisting of a polyaryl and a liquid-crystal polymer, wherein the polyaryl is selected from the group consisting of a poly(aryl ether sulfone), a polyaryletherketone, and a polyphenylene sulfide; providing an inner ring formed with, or consisting essentially of, liquid-silicone or polyurethane; and arranging the outer ring and the inner ring relative to one another with a form fitting engagement, to thereby form the sealing ring according to claim 1.

11. The method according to claim 10, which comprises forming the inner ring with at least one groove, the groove having a base and two opposite sides extending from the base, and placing the outer ring to engages in the groove with a form fit.

12. The method according to claim 11, which comprises forming the outer ring with at least one aperture and providing the inner ring with at least one bar that extends from one side of the groove to the other side of the groove, and passing the at least one bar through the at least one aperture.

13. The method according to claim 12, wherein the at least one aperture formed in said outer ring is a slot.

14. The method according to claim 10, which comprises forming the outer ring with an injection molding process, and polishing or cleaning the outer ring after the injection molding process.

15. The method according to claim 10, which comprises forming the inner ring with an injection molding process.

16. The method according to claim 15, which comprises injection-molding the inner ring around the outer ring and arranging the inner ring with a form-fit to the outer ring.

17. The method according to claim 10, which comprises pre-treating the outer ring prior to being arranged in the form-fit engagement with the inner ring.

18. The method according to claim 17, which comprises pre-treating the outer ring prior to being overmolded by the inner ring.

19. The method according to claim 17, which comprises pre-treating the outer ring with use of a plasma or an adhesion promoter.

Description

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

[0053] FIG. 1A and FIG. 1B show perspective, schematic views of an embodiment of the sealing ring according to the invention;

[0054] FIG. 2 shows a schematic view of an embodiment of the production method according to the invention; and

[0055] FIG. 3A and FIG. 3B are sectional views of an embodiment of the contact socket according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

[0056] Referring now to the figures of the drawing in detail and first, particularly, to FIGS. 1A and 1B thereof, the present invention relates in particular to a sealing element 100 made of a PSU component 10 and an overmolding 20 made of LSR (liquid silicone rubber). The PSU component is designed here in particular as an outer ring 10, and the LSR overmolding is designed as an inner ring 20.

[0057] The PSU core 10 performs the following functions and has the following advantages: [0058] distance between 2 electrical contacts [0059] limit stop for the assembly process [0060] attachment surface for resin for forming the header [0061] mechanical fixing to the silicone (apertures) [0062] attachment surface for silicone possibly for plasma processes or primer

[0063] The LSR overmolding 20 performs the following functions and has the following advantages: [0064] electrical insulation between two electrical contacts (provided by spherical end-face sealing surfaces of the inner ring, which leads to a form-fit connection between the electrical contacts, when the contact socket is clamped) [0065] potential separation between electrode and cavity [0066] seal against infiltration of resin during the resin casting (realised by the defined limit stop surface and resultant technical zero gap between the PSU rim and the housing of the electrical contact).
These constitute three independent sealing functions.

[0067] FIG. 1A illustrates an embodiment of the sealing ring 100 according to the invention which consists of an outer ring 10 made of PSU and an inner ring 20 made of a liquid silicone or liquid-silicone rubber. FIG. 1B shows a detailed view of the outer ring 10 and of the inner ring 20. The outer ring 10 has slots 13 (apertures), which are used to grip or claw the inner ring 20 made of LSR. The inner ring 20 in turn forms a groove 21, which comprises a base 22 and two opposite walls, which extend from the base. The outer ring advantageously has 2 or 3 bars, which extend from a wall 23 of the groove 21 to the other wall 23 of the groove 21. These bars 24 each pass through a corresponding slot in the outer ring 10 and thus ensure a form-fit connection between the inner ring 20 and outer ring 10.

[0068] The outer ring 10 is used in particular as a limit stop for assembly of the electrical contacts 30. Due to the used PSU, a particularly good attachment to the epoxy resin that is used during course of manufacture of the header is possible, and this thus contributes to the electrical insulation above the PSU core. In addition, the outer ring serves as a guide for the wiring ribbons between the electrical contacts 30, for example of an 8-pole module, an an electrical feedthrough to the interior of the housing. This assists the process in which the wiring ribbons are welded onto the electrical contact 30. By design, an potential separation of the wiring ribbons is thus also realised.

[0069] FIG. 2 shows a flowchart that outlines the manufacture of the sealing ring 100 according to the invention. The PSU core or outer ring 10 is firstly provided by an injection molding process. As appropriate, the outer ring 10 is pre-treated by a vibratory finishing (barrel finishing) or by a cleaning process. The outer ring 10 is preferably additionally plasma-treated or primed (treatment with an adhesion promoter) to provide improved adhesion of the LSR 20. LSR is then injection-molded around the outer ring 10, wherein the LSR then forms the inner ring 20. If the outer ring 10 has slots 13, these are filled by the LSR, wherein an inner ring 20 with groove 21 and bars 24 is thus formed, wherein the bars 24 then pass through the corresponding slots 13, and a form-fit connection is formed between outer ring 10 and inner ring 20.

[0070] FIG. 3A shows schematic sectional view of a contact socket 200 according to the invention, with FIG. 3B showing an enlarged partial view. The contact socket has a plurality of electrical contacts 30, in particular spring contacts, between each two of which a sealing ring 10 according to the invention is arranged. The contact socket 200 has a cavity in its interior, in particular a cylindrical cavity, which is designed to receive a plug of an electrode lead. Here, the electrical contacts 30 are used to conduct a current or electrical pulse between the plug of the electrode lead and the current-emitting or current-detecting components of an implantable device (for example ICD), which are accommodated in the housing of the device. The electrical contacts 30 are connected to the interior of the housing in particular via wiring ribbons.

[0071] In order to provide the liquid silicone, the components A and B, the 40 Shore Material LSR Silastic 7-6840 (Dow Corning Corporation), were mixed with one another in a ratio of 1:1 and were annealed or tempered to provide an improved final cross-linking of the silicone material in a circulating air furnace (=post cure process). In principle, however, other Shore hardnesses of the LSR Silastic product family are also suitable, for example 30, 50 or 60. The temperature of the tempering is dependent in particular on the material of the core, in particular on its melting point or glass transition temperature. In the case of a PSU core 10, tempering is performed at a temperature of approximately 150° C. for 12 hours. In the case of a PEEK core 10 higher temperatures may be used. Alternatively, liquid silicones of the Silpuran 6600 product family with Shore hardnesses between 40 and 60 can also be used.